LONG-TERM EFFECTS OF A SINGLE INCIDENCE OF HIGH AXLE LOAD COMPACTION ON A CLAY SOIL IN QUEBEC

The long-term effects of a single incidence of compactive loads of 12 and 20 Mg per axle on a clay soil are evaluated. Changes in soil bulk density and crop performance under monocultural row production were monitored over the 7 year period following loading. Soil bulk densities were significantly increased by the initial high axle load compaction. Bulk densities in both compacted and uncompacted plots continued to increase in a monocultural corn production system. The effect of residual compaction on total plant dry matter yields lasted for 4 years. Grain yield reductions persisted for up to 6 years after compaction. In both cases, however, yields showed an improving trend throughout the study period.